The Invisible Constitution in Comparative Perspective

Part III

The View from Europe and North America

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15

The Evolution of Natural Law in Ireland

Eoin Carolan

15.1. Introduction

From an Irish perspective, the notion of an ‘invisible constitution’ most  

obviously calls to mind the controversy over the influence of natural law phi-

losophy on Ireland’s constitutional order. The Constitution of Ireland contains 

several provisions which can be plausibly construed as having a natural law 

dimension. Quite what these allusions to an external moral code meant for 

constitutional practice, however, proved contentious. This partly reflected the 

Constitution’s lack of textual clarity on these questions. It can also be traced, 

however, to the contestable character and content of this ‘natural law’ itself. 

Acknowledged but ambiguous, endorsed but arguably unknowable, natural 

law provides perhaps the most high-profile experiment in Ireland with an 

‘invisible’ constitutional resource. It serves therefore as the most relevant Irish 

source of reflection on this theme.

This chapter is divided into a number of sections. Section 

15.2

 describes the 

history of natural law references in Irish constitutional jurisprudence. This 

section sets out the conventional narrative, which is that natural law enjoyed 

a period of prominence during the period between the mid-1960s and mid-

1990s before being decisively and completely rejected by the Supreme Court 

in its Abortion Information Bill decision in 1995.

1

 This heralded the ‘death of 

natural law’ within the Irish legal system.

2

The next section of the chapter challenges that narrative in several respects. 

It is argued, first of all, that the ‘death of the natural law’ narrative is based on a 

series of questionable assumptions about the natural law jurisprudence of the 

1 

In re Article 26 and the Regulation of Information (Services outside the State for the Termination 

of Pregnancies) Bill 1995 [1995] 1 IR 1 (‘the Abortion Information Bill’ reference).

2 

Adrian F. Twomey, ‘The Death of the Natural Law?’ (1995) 13 Irish Law Times 270.

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Eoin Carolan

Irish courts in the 1960s to 1990s. A careful reading of the case law from this 

period confirms that the Supreme Court’s 1995 decision was not necessarily 

inconsistent with (at least some of) the judicial determinations that preceded it.

Nor, it is suggested, does it necessarily mean the end of natural law in 

Ireland. The second argument advanced in Section 

15.3

 is that the Supreme 

Court continues to draw on natural-law-style reasoning in some of its recent 

cases. Specifically, the Supreme Court’s willingness to have regard to values 

of dignity, autonomy and justice in certain instances of constitutional adju-

dication bears comparison, in some respects, with the earlier invocations of 

natural law. While the terminology and (perhaps) content of these ‘invisible’ 

norms may have changed, their interpretative potential as extra-textual sources 

of constitutional understanding seems broadly similar.

The final section of the chapter considers the implications of this analysis 

for the book’s wider interest in ‘invisible’ constitutional values. In particular, 

the fact that the Irish courts continue to make use of quasi-moral or normative 

concepts that are not clearly enumerated in the text, that are ambiguous in 

their content and that may carry with them connotations of inalienability is 

argued to suggest either a reluctance or inability to rely on purely textual read-

ings alone. Section 

15.4

 considers why this might be the case. What the Irish 

experience indicates, the chapter tentatively concludes, is that there may be 

social and systemic benefits to a degree of opacity in the constitutional order.

15.2.  Natural Law and the Constitution of Ireland